This invention relates to a putter-type golf club head with increased geometric size, increased moment of inertia, increased sole area, lie angle adjustability and decreased loft. Herein use of the word “putter” is intended to refer particularly to head of the putter.
Generally, increasing geometric size (linear dimensions) increases the moment of inertia for a putter head of a given mass. Herein, references to “moment of inertia” (MOI) relate to mass properties. Increasing moment of inertia increases the stability of the putter at impact and increased stability is desirable in a putter. A force is exerted on both a golf club and a golf ball when the club hits the ball. If the hit is slightly off-center (e.g., the center of mass of the golf club head is not directly behind the point on the golf club face where the club strikes the ball), then the forces will cause the golf club to twist slightly. The twisting of the golf club leads to the ball not traveling in the direction intended by the player or not rolling smoothly. Additionally, less energy is imparted to the golf ball when the putter twists. This commonly causes off-center hits to fall short of their intended target. Increasing the moment of inertia of the putter head decreases the tendency for the putter head to twist when hitting the ball.
The “loft” of a putter is generally understood to be the deviation of the plane of contact on a putter face from a vertical plane (the putter shaft being in the vertical plane). The standard loft on putters has decreased dramatically over time as golf greens have become better groomed and much faster than in previous times. Putters' lofts in earlier times have been as high as 7 degrees. A loft of about three or four degrees is standard today. Loft on putter faces causes the golf ball to leave the putter face with an upward trajectory and with backspin. This backspin causes the ball to skid and bounce before it later begins to roll smoothly. Reducing loft will reduce backspin, skidding and bouncing.
The standard lie angle of putters today is about 20 degrees from vertical. The “lie angle” here follows the common understanding of the term: the angle of the shaft from the vertical (in a plane perpendicular to the intended direction of travel of the ball in play) when the putter head is placed in its intended attitude on the ground. The sole (bottom face) of most putters is curved raising both the toe and heal of the putter off of the ground when the putter is soled at its center. Testing has confirmed that most golfers are using a putter with too little lie angle causing the toe of the putter to be further raised when the ball is addressed. Golf professionals seem to prefer slightly more upright putters than the general golfing public and golf club manufacturers have designed their putters with professional golfers. Most golf putter manufacturers have been unwilling to provide custom lie angles for their putter offerings; and pro shops and retailers have been similarly unwilling to stock all of the putters of every single model in multiple lie angles. The result is that most golfers are playing with a putter that is slightly too upright and the consequence of this poorly fitted putter is that the toe is most commonly slightly raised off the ground and the heal of the putter is soled on the ground. Herein the use of the word “sole” as a verb means to place the putter on or adjacent a playing surface in an attitude to strike a ball as intended.
With the putter toe in the air the loft of most putter faces will cause the ball to start to left of the actual aim line of the putter (for right-handed golfers). Because of this most golfers have subliminally learned to aim slightly to the right of their intended target and then the loft of the toe high putter pulls the putt back onto the intended line. The loft on a toe high putter also induces unwanted spin on the ball. Decreasing the loft of a putter decreases the problems associated with a toe high-lofted putter. Eliminating all loft on the putter eliminates the problem entirely.
The curved sole design of most putters makes them very difficult to sole on the ground accurately and consistently. A flat sole of significant area will allow the golfer to more consistently align the putter.
In light of the above, there is a need for a putter with decreased loft, higher moment of inertia and adjustable lie angle.